* Backport StackUtils class from Helma 2.

* Implement jsStackTrace option to generate pure JS stack traces in error dumps.

src/helma/framework/core/Application.java

@@ -1366,8 +1366,13 @@ public final class Application implements Runnable {
         if (eventLog == null) {
             eventLog = getLogger(eventLogName);
         }
-
+        if ("true".equalsIgnoreCase(props.getProperty("jsStackTrace"))) {
-        eventLog.error(msg, error);
+            Exception jsx = new RuntimeException(error);
+            StackUtils.setJavaScriptStack(error, jsx);
+            eventLog.error(msg, jsx);
+        } else {
+            eventLog.error(msg, error);
+        }
     }
 
     /**

src/helma/util/StackUtils.java

@@ -0,0 +1,47 @@
+/*
+ *  Copyright 2006 Hannes Wallnoefer <hannes@helma.at>
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package helma.util;
+
+import java.util.List;
+import java.util.ArrayList;
+
+/**
+ * Utility class to extract pure JavaScript stack trace from Java exceptions
+ */
+public class StackUtils {
+
+    /**
+     * Extract the JavaScript stack trace element from the source exception
+     * and copy them over to the target exception.
+     * @param source the source exception
+     * @param target the target excepiton
+     */
+    public static void setJavaScriptStack(Throwable source, Throwable target) {
+        List list = new ArrayList();
+        StackTraceElement[] stack = source.getStackTrace();
+        for (int i = 0; i < stack.length; i++) {
+            StackTraceElement e = stack[i];
+            String name = e.getFileName();
+            if (e.getLineNumber() > -1 &&
+                    (name.endsWith(".js") || name.endsWith(".hac"))) {
+                list.add(e);
+            }
+        }
+        target.setStackTrace((StackTraceElement[]) list.toArray(new StackTraceElement[list.size()]));
+    }
+
+}